The objective of this research project is to develop a prototype app for wearable technology that will significantly enhance the effectiveness of our web-based alcohol and drug intervention, Checkup&Choices (CC). We have already demonstrated the effectiveness of CC's components in four randomized clinical trials; CC has been commercialized and is in use by the general public. This project will improve the effectiveness of CC by utilizing recent methodological advances in the clinical assessment and treatment of target behaviors that have been made possible by advances in information technology. The long-term objective is not just to develop an app that will work across devices and platforms in support of CC, although we do intend to do that in Phase II, but further, to contribute to and advance the field of tech-based interventions for drug and alcohol abuse. The major project goals in Phase I are to work with a group of individuals who are interested in moderating their drinking, and who have a demonstrated interest in using technology to do so. Our team of clinicians and software engineers will iteratively develop the prototype app, the interface between the app and the CC program, and the new treatment components within the CC program made available through the new app. In this Phase I study, given the limited time frame, our intent is to focus on usability and feasibility and as such, the features we will develop for the prototype will be simple and fundamental: prompts to enter drinking data, the ability to capture the data, real-time feedback on blood-alcohol content and drinking limits, and interface with the CC program. Subsequent development of the app created in Phase I will be informed by our research into the clinical benefits of this technology, as well as ongoing advances in wearable technology. The ability of technology to convey treatment components into the context in which problematic behaviors occur is revolutionizing the field of clinical psychology. Although alcohol and drug addictions have traditionally been some of the most difficult psychological disorders to treat, they are particularly amenable to the present innovation because the behaviors in question are simple to specify, and highly sensitive to context. Given the human suffering and financial cost associated with alcohol and substance abuse, this innovation has significant potential to reduce the burden these disorders place on the people who use it, as well as their family and friends, and society at large.